The present invention relates to a method for producing a polymer-particle composite capable of forming a display material such as a light diffusion plate, an optical material such as a colloidal crystal, a building material such as a wallpaper, a noncombustible material, a catalyst material, a separation membrane, an electrode material, a decorative paper, a film, an accessory and a toy.
Recently, there is an increasing interest on a nm- or μm-sized particle because of an industrial utility which varies depending on the particle size. For example, a dendrimer having a particle size of several nanometers to several ten nanometers has a specific property such as antenna effect, while a metal particle or a semiconductor particle having a particle size of several nanometers to several ten nanometers is expected to be applicable to a device material utilizing a quantum effect. An oxide particle having a particle size of several nanometers to several ten nanometers is also applicable to an abrasive, a film filler, a paint filler, a ceramic additive, a pigment, a fluorescent substrate, a magnetic material and the like, while an oxide or a polymeric particle having a submicron particle size is applicable to an optical material such as a colloidal crystal and a photonic crystal. Furthermore, an oxide or a polymeric particle having a particle size of several micrometers to several ten micrometers is expected to be applicable to an optical material such as a light diffusion plate, and a light diffusion plate for a display employing an oxide particle has already been used practically.
In the industrial field of application described above, an efficient utilization of the characteristics of a particle requires a regular or random inclusion of the particle in a support material such as a polymeric material without aggregation of the particle. A technology for such inclusion is considered to be very important in these days, and various methods have been reported.
For example, a colloidal crystal was produced by a method for obtaining a colloidal crystal in a dispersion (JP-A-5-85716, JP-A-6-335629), a sedimentation method (Ceffe Lopez et al., Advanced Materials, vol. 9, No. 3, pp 257-260 (1997), an electrophoretic method (Ceffe Lopez et al., Langmuir, vol. 15, pp 4701-4704 (1999)), a solvent evaporation method (L. F. Chi et al., Langmuir, vol. 13, pp7121-7124 (1997)), a vertical deposition method (JP 2905712), an electrostatic interaction method (Amy E. Larsen et al., Nature, vol. 385, pp230-233 (1997)), a spin coating method (Richard P. Van Duyne et al., Journal of Vacuum Science and Technology (A) vol. 13, pp 1553-1558 (1995)), an injection method (Younan Xie et al., Advance Materials, vol. 10, pp. 1028 (1998)), a matrix polymerization method (U.S. Pat. No. 4,451,412) and the like. However, any of the methods described above involves a problematic disadvantage, such as a prolonged production time, a difficulty or an impossibility experienced in controlling the film thickness, the requirement of a cell or a sealing, the lack of self-standing ability, and the like.
While a method in which a liquid formulation containing a polymeric material and a particle is applied onto a substrate and then the medium is evaporated off has also been employed, it allows the particle to be aggregated readily when the particle is small, and involves a problematic limitation with regard to the particle content.